Compressors

ABSTRACT

In a compressor of eccentric vane type having means for separating oil from compressed air, the oil-laden air from the cylinder enters the centre of a primary separation chamber and flows in two streams towards opposite ends, spreading out and following a sinuous path.

United States Patent 1191 Rudge Oct. 30, 1973 COMPRESSORS [56] References Cited [75] Inventor: Peter John Rudge, Redditch, UNITED STATES PATENTS England 738,101 9/1903 Curtis 418/262 Assignee: The nydrovane Compressor 3,45l,l98 6/l969 Axelsson 55/430 Company, Limited, Reddim FOREIGN PATENTS 0R APPLICATIONS England I l,l34 ,224 1 H1968 Great Britain 55/437 22 Filed: 1m. 23, 1970 A App]. 110.; 101,087

Foreign Application Priority Data 1 Dec. 24, 1969 Great Britain 62,795/69 Primary Examiner Bernard Nozick Att0rneyWatson, Cole, Grindler & Watson [57] ABSTRACT In a compressor of eccentric vane type having means for separating oil from compressedjair, the oil-laden air from the cylinder enters the centre of a primary separation chamber and flows in two streams towards opposite ends, spreading out and following a sinuous path.

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' ATTORNEYS COMPRESSORS This invention relates to compressors of eccentric vane type and in particular to means for separating oil from compressed air.

According to the present invention a compressor of eccentric vane type includes a rotor having a number of sliding vanes mounted to rotate about an eccentric axis, in a cylinder in a stator, in which the crescent shaped space is divided by the vanes into a number of working chambers, and has means for delivering oil into the working chamber, and/or the air inlet thereto, from a sump surrounding the lower part of the stator, characterised in that the stator is connected to the centre of a primary separation chamber, which surrounds the upper part of the stator, and .in which the air/oil mixture, flowing from the stator, flows in two streams towards opposite ends of the primary separation chamber. As the air/oil mixture flows through the primary separation chamber it may be caused to spread out in order to reach ports which communicate with a final oil separator.

The primary separation chamber may have circumferential inwardly projecting, spaced flanges, in planes at right angles to the axis of the cylinder, the dimensions of the flanges being such that the air/oil mixture may pass between the stator and the extreme points of the flanges. In addition, the stator may have circumferential outwardly projecting flanges in planes at right angles to the axis of the cylinder, situated between the inwardly projecting flanges of the primary separation chamber causing the air/oil mixture to flow in a labyrinthine path.

As the velocity of the air/oil mixture has a considerable effect on the efficiency of the primary separation the present invention provides for more effective separation as it splits the flow, from the stator as it enters the primary separation chamber, into two streams and preferably causes each stream to spread out thereby reducing velocity, and causes the air/oil mixture to follow a longer labyrinthine path. Further divisions ofthe flow may be obtained by increasing the number of ports, and/or repositioning the ports, by which the primary separation chamber communicates with the final oil separator.

Preferably the final separator is arranged so that the two streams of air flow in it towards a central outlet.

The invention may be put into practice in various ways but one specific embodiment will now be briefly described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional elevation of a compressor incorporating an oilseparator in accordance with the invention, and

FIG. 2 is a sectional end view of the compressor shown in FIG. 1.

The compressor may be substantially as described in British Patent Specification No. 1 134224 or British Patent Specification No. 38000/69, both commonly owned herewith.

As the present invention is concerned only with the separation of oil from compressed air it is not considered necessary to describe the actual construction of the compressor in great detail and it may be considered to be substantially the same as that described in British Patent Specification No. 1 134224.

Thus the compressor consists of a casing the lower part of which has in it a cylinder 11, in a stator, in which a shaft 12 rotates about an axis which is eccentric to that of the cylinder 1 1. The shaft carries a rotor 14 having in it a number of axial grooves which receive sliding vanes 15 whereof the outer edges engage the surface of the cylinder 11. Air is drawn in through inlet ports 19 from inlet manifolds 18 extending along the bottom of the stator 17 and after being compressed in the crescent-shaped working space between the rotor 14 and the cylinder 11 is delivered through delivery ports (26) into a delivery manifold 24 extending above the top of the cylinder 11 in the upper part of the stator 17.

At an intermediate point 28 of the crescent-shaped working space, oil is admitted to the air which travels with the oil entrained in it through the delivery manifold 24 and from the centre of which it flows out into a primary separation chamber 25. Here it divides into two streams, one flowing towards each end of the separation chamber, and follows labyrinthine paths and during its passage about 99.95 percent of the oil is separated from the air and drains down round the outside of the stator 17 to a sump 30 beneath it. Thus the stator 17 has on it shallow external circumferential flanges 20 and the primary separation chamber has deeper interpath. Along a line parallel to the axis through the port 22 additional flanges 23 are provided on the stator 17 abutting those in the primary separation chamber but only of short circumferential extent to cause the air to spread out circumferentially and prevent it from flowing in a straight line as viewed in plan.

The air, with the remaining oil, passes up from the ends of the primary separation chamber 25 through cast ports 32 and drilled holes 33-to the ends of a generally cylindrical final separation chamber 37 which occupies the upper part of the casing 10.

In the final separation chamber 37 the two streams flow towards a central delivery connection 50 from the complete compressor, which opens from the centre of the final separation chamber 37. The intermediate parts of the chamber 37 contain a series of thick felt discs or pads 38 made from compressed wool felt or other suitable material completely filling the crosssection of the chamber 37 and alternating with baffles 39 throughout the major part of its length. In use the pads become saturated with oil separated from the air- ./oil mixture and the oil trickles from the downstream faces of the pads and forms pools in a number of wells 40 distributed along the length of the chamber 37.

Opening out of each well is a rising passage 41 having its lower end submerged in the pool. The upper end has a screw threaded portion which receives a plug 42 accommodating a filter 43 and fixed orifice 44. This filter ensures that any foreign bodies such as portions of the pads cannot reach and block the orifice.

Adjacent to this rising passage 41 is a further passage (not shown) leading down to a cavity 46 beneath the casing of the separator 37 from where the separated oil is drained back to the intake of the compressor. A cap 47 covers both passages and connects them together.

What we claim as our invention and desire to secure by Letters Patent is:

l. A compressor of eccentric vane type including a stator having in it a cylinder, a part annular sump surrounding the lower portion of the cylinder and a part annular primary separation chamber surrounding the upper portion of the cylinder, a rotor mounted eccentrically in the cylinder and having a number of sliding vanes dividing the crescent shaped space between the rotor and cylinder into a number of working chambers, means for delivering oil into air flowing through the compressor, means defining a final separation chamber extending parallel to and adjacent the primary separation chamber, straining means in the final separation chamber, and conduit means for directing oil-laden compressed air from the working chambers to the center of the primary separation chamber to flow in two streams therein toward opposite ends thereof, means in the primary separation chamber causing substantial separation of the oil from the air for each of the two streams, ports connecting the ends of the primary separation chamber respectively to the ends of the final separation chamber for the passage of said two streams into the latter, wherein they can flow toward the center thereof through the straining means, and means defining an outlet for the air from the center of the final separation chamber.

2. A compressor as claimed in claim 1, in which there are at least two of said ports circumferentially spaced between the primary separation chamber and the final separator at each end of the primary separation chamber.

3. A compressor as claimed in claim 1, in which said means in the primary separation chamber causing substantial separation include circumferential inwardly projecting, spaced flanges, in planes at right angles to the axis of the cylinder, the inwardly projecting dimensions of the flanges being such that the air/oil misture passes between the stator and the extreme points of the flanges.

4. A compressor as claimed in claim 3, in which the stator has circumferential outwardly projecting flanges in planes at right angles to the axis of the cylinder, located between the inwardly projecting flanges of the primary separation chamber thereby causing the air/oil mixture to flow in a labyrinthine path.

5. A compressor as claimed in claim 4, in which the stator has additional outwardly projecting flanges in planes at right angles to the axis of the cylinder and of short circumferential extent to cause each stream to spread out thereby reducing velocity, and thereby causing the air/oil mixture to follow a longer labyrinthine path. 

1. A compressor of eccentric vane type including a stator having in it a cylinder, a part annular sump surrounding the lower portion of the cylinder and a part annular primary separation chamber surrounding the upper portion of the cylinder, a rotor mounted eccentrically in the cylinder and having a number of sliding vanes dividing the crescent shaped space between the rotor and cylinder into a number of working chambers, means for delivering oil into air flowIng through the compressor, means defining a final separation chamber extending parallel to and adjacent the primary separation chamber, straining means in the final separation chamber, and conduit means for directing oilladen compressed air from the working chambers to the center of the primary separation chamber to flow in two streams therein toward opposite ends thereof, means in the primary separation chamber causing substantial separation of the oil from the air for each of the two streams, ports connecting the ends of the primary separation chamber respectively to the ends of the final separation chamber for the passage of said two streams into the latter, wherein they can flow toward the center thereof through the straining means, and means defining an outlet for the air from the center of the final separation chamber.
 2. A compressor as claimed in claim 1, in which there are at least two of said ports circumferentially spaced between the primary separation chamber and the final separator at each end of the primary separation chamber.
 3. A compressor as claimed in claim 1, in which said means in the primary separation chamber causing substantial separation include circumferential inwardly projecting, spaced flanges, in planes at right angles to the axis of the cylinder, the inwardly projecting dimensions of the flanges being such that the air/oil misture passes between the stator and the extreme points of the flanges.
 4. A compressor as claimed in claim 3, in which the stator has circumferential outwardly projecting flanges in planes at right angles to the axis of the cylinder, located between the inwardly projecting flanges of the primary separation chamber thereby causing the air/oil mixture to flow in a labyrinthine path.
 5. A compressor as claimed in claim 4, in which the stator has additional outwardly projecting flanges in planes at right angles to the axis of the cylinder and of short circumferential extent to cause each stream to spread out thereby reducing velocity, and thereby causing the air/oil mixture to follow a longer labyrinthine path. 